Worm-gear.



UNTTED; STATES PATENT OFFICE.

GUSTAV STAEHLE,` OF STUTTGART, GERMANY.

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SPECIFICATION formingpart of Letters Patent No. 718,398, dated January 13, 1903.

Y ilpplioation filed August 2, 1902- Serial No. 118,099. (No model.)

To a/ZZ whom it may concern:

Be it known that I, GUsTAv STAEHLE, a citi- Zen of the Empire of Germany, residing in Stuttgart, Germany, have invented certain new and useful Improvements in Worm- Gears,of which the following is a specification.

The wormgear though well adapted for transmission of power on a large scale is but little employed in such cases, as there is a considerable loss of power by thegreat friction that takes place between the parts of the same. Attempts were therefore made to provide worms and wormgears with antifriction-rollers, so as to obviate the loss of power by friction in Worm-gear transmissions; but the arrangement of the roller-bearings in worm gear-wheels did not meet the requirements of practical use, so that their use was limited to few applications. The support of the rollers in the worm-gears was objectionable on account of the one-sided action on the pivot-shafts and on rollers, by which bending or breaking of the pivots and interruption in the running of the worm-gear wereA caused.

My improved worm-gear is designed to overcome the defects referred to and to furnish'a very reliable and effective gear for all applications; and for this-purpose the invention consists of a worm-gear in which the-worm gear-Wheel is provided with antifriction-roll'- ers in place of teeth, the shafts of the rollers being supported at both ends; and the invention consists, further, of a worm gear-Wheel providedwith antifriction-rollers the shafts of which are supported at both ends by means of outwardly-projecting offset lugs connected by transverse bridge-pieces, said lugs and bridge-pieces having inclined side faces, so that in case of breakage of one of the shafts said lugs` can take the place and act in the nature of teeth without interrupting the working of the worm-gear.

In the accompanying drawings, Figure l is a side-elevation, partly in section, and Fig. -2 an end elevation, also partly in section, of my improved worm-gear.

Similar letters of reference indicate corresponding parts.

The worm a is of the usual construction,y with smooth convolutions. The worm gearwheel d is not provided with teeth but in place of the same antifriction-rollers b are substituted, which are supported on shafts c, that are arranged radially on the circumference of the worm gear-wheel d. These shafts c, however, are not only supported at their inner ends in the circumference of the worm gearwheel d, but also at their outer ends in transversebridge-pieces f of outwardly-extending lugs e, Vwhich are preferably made integral withthe circumference of the gear-Wheel d.

The outwardly-extending lugs e at opposite sides of the circumference of the gear-wheel d extend radially from the circumference and are offset toward each other in such a manner that thelugs in one side of the wheel are in advance of those on the other side, so that the inclination'of their side faces e' and the inclination of the side faces f' of the transverse bridge-pieces f correspond to the screw-pitch of the worm a. The interstices between the adjacent lugs e and the transverse bridgepieces f are so arranged that the convolutions ofthe Worm can move freely within the same. This arrangement has the further advantage that in case of the breakage of one of the roller-shafts c the worm-gear is not placed outV of use and the transmission of motion interruptedi for the reason that the faces e' and f' of the outwardly-extending lugs e and transverse bridge-pieces f, respectively, take the place of the roller and act in the nature of teeth, so that the motion of the worm-gear can vbe kept up until a new roller-shaft c can be substituted for the broken shaft. It isy necessary that some of the bridge-pieces for the rollershafts should be made independently of and detachably from the gear-wheel, while the remaining ones can be made integral therewith. In this case, however, the rollers have to be introduced at the points where the separable bridge-pieces are located and have then to be passed gradually from one pair of lugs to the other until they can be held in position by the insertion of the roller shafts through the hubs of the rollers, said shafts being then fastenedby being secured in their bearings in the circumference of the wheel and the bridge-pieces of the outwardly-extending lugs.

Having thus described my invention, I claim-as new and desire to secure by Letters Patent- TOO In a Worm-gear, the combination With a I pieces, and antifriction-rollers on said shaft, driving screw or Worm, of a Worin gear-Wheel substantially as set forth. provided at its circumference with outward In testimony that I claim the foregoing as radialiyextending lugs set off at opposite my invention I have signed my namein pres- 5 sides of said circumference so that the lugs ence of two subscribing Witnesses.

on one side of the Wheel are in advance of f 1 those on the other, bridge-pieces connecting GUS FAV STALHLE the ends of the oset lugs, radial shafts sup- Witnesses:

ported between the lugs by the eircurnfer- CONRAD ZEISIG,

Io ence of the worm gear-Wheel and the bridge- ERNST CUTENMAN. 

